[paperboyNC]

You need a read on the villian. Against most 2/4 players, this is a turn fold. You have 4 outs to a boat, but you are only getting 6-1 from the pot (10-1 to make your boat).

Once you call the turn, you have to call the river getting 8-1 with no reverse implied odds.

That's why you fold the turn against most opponents. You are really getting 7-2 on a call down and you aren't good the 30% of the time you need.